A longer decay is not going to solve your high frequency problem. High frequencies
will bypass large capacitance. You need to filter the unwanted frequency. This is
why you may see a U10 (0.10uf) capacitor across a electrolytic. The electrolytic
takes care of the low frequencies, the U10 takes care of higher frequencies.
Rick

Alessandro Queri wrote:

> That's it, BUT! I need to start at a lower voltage, not to mention the
> negative supply... The big capacitance would give a longer decay. What you
> show, essentially is a LPF. Problem occur just before that, on the
> switching part. Thus make also the 5Vcc part compromised by ripple due to
> charging big capacitors via FET or something like that.
>
> I'll try the modules you suggested, maybe LPFing them with PI filters on
> input and LPF+PI on outputs.
>
> Cheers!
>
> Ale
>
> On Wed, 3 Dec 2003, Rick C. wrote:
>
> > The easiest way to achieve that purity is to use a series of resistors and
> > capacitors, maybe two or three stages to isolate any possible ripple. You need
> > not use large capacitors. They will not impede the ripple.
> >
> > -----r-----r-----> +
> >            |        |
> >            c       c
> >            |        |
> > ----------------->G
> >            |        |
> >            c       c
> >            |        |
> > -----r----r-------> -
> >
> > Rick
> >
> >
> > --

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